Lawyers for Charles Rhines say that they have evidence that the jury gave him the death penalty because they believed that prison would be too much fun for a gay man, possibly referring to the prevalence of male rape in prison.

Rhines murdered Donnivan Schaeffer, 22, in 1992. Schaeffer was an employee of Dig ‘Em Donuts in Rapid City, South Dakota, when Rhines tried to rob the shop.

In 1993, Rhines was convicted of stabbing Schaeffer to death, and was given the death penalty. But defense lawyers are trying to get the Supreme Court to hear their appeal to overturn the death penalty, saying that the jury’s decision is tainted by homophobia.

Juror Frances Cersosimo said that she remembers a juror saying that Rhines wouldn’t mind life in prison because he’s gay. “There was a murmuring, everyone said ‘Whaaat?’” she said.

“It was not a joke,” she said.

In an affidavit presented to the Supreme Court, juror Harry Keenan said that his decision was affected by homophobia. But Keenan’s wife said that he has dementia and that his memory of something that happened 25 years ago isn’t reliable.

“I wouldn’t depend upon it,” Keenan’s wife said.

In another affidavit, a third juror said that another juror said that a sentence of life in prison would be “sending him where he wants to go.”

The defense attorneys also point to questions the jury asked the judge during sentencing in 1993, which included: What would his life in prison look like? Would he be allowed to mix with the general inmate population? Would he have a cellmate?

The judge said that he couldn’t answer those questions.

Rhines has long argued that he was sentenced to death because he’s gay. In addition to the comments about prison being too much fun for a gay man, he said in 2014 that prosecutors portrayed him as a dangerous “sexual predator” even though his crime did not involve sexual assault.

Lawyers for the state of South Dakota, though, shot back, saying that the jury had ample grounds for giving Rhines the death penalty.

“Rhines locked Donnivan’s head between his knees and pounded a hunting knife into the base of Donnivan’s skull, partially severing his brain stem,” the assistant attorney general’s brief reads. “Unaffected by the screams and blood and death, Rhines left the store with his loot to get something to eat.”

Generally, the jury’s discussion is not grounds to overturn a sentencing, under the “no-impeachment rule.” But several recent Supreme Court decisions have opened the door to examining juries’ bias.

Last year, in Pena-Rodriguez v. Colorado, a man was convicted of sexually assaulting two girls, but one of the jurors said, “Nine times out of ten Mexican men were guilty of being aggressive toward women and young girls,” and “Mexican men had a bravado that caused them to believe they could do whatever they wanted with women.”

The Supreme Court ruled that the statements showed that the defendant’s Sixth Amendment rights were violated because the jury decided that he “was guilty and his alibi witness should not be believed” because of a racist juror. The case was sent back to the lower courts.

It’s possible for the Supreme Court to extend that logic to sexual orientation, especially since studies have shown that gay men are more likely to be found guilty by juries and that the death penalty is less likely in cases involving gay victims.